where did the water go?

[Olonam]

A newbie here...

I own a 2001 Trooper. Got it 2nd hand.

I brought the Trooper to Isuzu Pasig for the following: 45,000 tune up and to check on the hard start, and increase in temperature which resulted in a check engine. The temp went to as high as 3/4 of the gauge. Almost a week later, I was told that I needed to change the thermostat. This was done. Numerous tests were done and the Trooper passed almost all the tests. Various water pressure and water tests were done. There was a finding, however, of loss compression in one of the cylinders and a top overhaul, replacement of injectors, and rail pressure control valve were recommended (WOW). Due to the prohibitive cost, and considering that various tests were done on the Trooper only in April, I was considering a second opinion. So I took the Trooper out last Saturday.

On Sunday, after driving for some 15 minutes, I noticed that the temp was beginning to rise again! This would occur when RPM was around 2000, but would recede when idle. I took it back on Tuesday, with a note that there was a significant drop in water level in the radiator (around 3 liters). Tests were done without any findings. Until the next Saturday, when Isuzu reported again a significant drop in water level. It was recommended to replace a coupling in the fan which was done as well as a clamp. Still, a drop in water level occurred. They surmise that the water is draining into the cylinder?!?!?!? (since they couldn't find an external drip).

To date, Isuzu Pasig has no exact finding. It wants to open engine to check. This is quite price prohibitive, and was not factored in the first set of tests in April nor in the 45,000 check up.

Any thoughts?